|Famiglia Name||Tomaso Famiglia|
|Allied Families||Vongola Famiglia|
The Tomaso Famiglia is supposedly a rival of the Vongola Famiglia, having said to have skirmishes in the second generation. However, their current leader-in-training, Longchamp Naito, seems more focused in making friends with Tsuna than actually starting a war with him, unaware of their rivalry (that, or he simply doesn't care). Also, just like Longchamp, his family is pretty eccentric in their own right, such as Longchamp's subordinates having frequent internal disputes. So far, only three known members of the Famiglia were shown.
It is suggested in the future that the Tomaso Famiglia remained close with Tsuna through the years, but nine years and ten months later, they are targeted by the Millefiore Famiglia. Two days prior to Tsuna's arrival in the future, Vongola has already lost all contact with them and they have since been reported missing.
The family's name is most likely based on the name of an Italian car company called De Tomaso. The company has produced cars such as the De Tomaso Longchamp, De Tomaso Mangusta, De Tomaso Pantera, and De Tomaso Vallelunga (Lunga), which are the names of the known Tomaso Family members.
The Tomaso Famiglia has so far been a manga only Famiglia, making no appearance in the anime version of the series due to its unpopularity.
Mangusta is the butler and tutor of Longchamp. He is the only one who takes the Famiglias' rivalry seriously and constantly tries to discourage Longchamp from being friends with Tsuna. He is also the holder of the Desolation Bullet which he uses to shoot Longchamp with, though he'll shoot anyone else, for that matter, to get them to agree with Longchamp's wishes.
Not much is known about Lunga, other than that he is trying to start a rock band. However, he seems to be having trouble recruiting members, threatening to send a bandmate back to his homeland for messing up a note.
Not much is known about Pantera, either, other than that she apparently tries to kill Longchamp very frequently. Her weapon of choice is bladed pinwheels. Longchamp only thinks she's kidding around in her attempts to kill him, however, and dodges her attacks by instinct. When Tsuna asked Mangusta if something happened between them, he nervously refused to comment, implying that something indeed happened (though what happened exactly was never stated).
They were many other members shown in an internal skirmish when Lambo had been sent flying into Naito's courtyard by Reborn.
- All of the members are named after cars from De Tomaso, an Italian car-manufacturing company.
- His family is the creator of the Desolation Bullet which, when shot with and revived, will cause a person to grieve about all the terrible things that have happened in their life, making others feel sorry for them.